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How can I avoid this?

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  #1  
Old 09-08-2008, 04:36 PM
sirespen sirespen is offline
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How can I avoid this?

First of all, sorry for that meaningless title! I don't even know how to call it.

How can I avoid this strange transition from the brighter tones to the darker?

And my second question is probably similar: When i render a light effect in photoshop and zoom to 100% i can see the gradients. How can i avoid that?

Greetings sebi

http://www.mediafire.com/imageview.p...emtlhe&thumb=5
http://www.mediafire.com/imageview.p...tmy5dd&thumb=5
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Old 09-08-2008, 05:09 PM
pixelzombie pixelzombie is offline
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Re: How can I avoid this?

it's called banding..try using the gradient tool instead of lighting effects...
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Old 09-08-2008, 05:18 PM
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TommyO TommyO is offline
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Re: How can I avoid this?

The way it looks, you may also have some other issues going on. Unfortunately, it's so small there is no way to tell. So, check for:
- color noise in the image;
- loss of image data (holes in your histogram);
- introduction of other color into that area of the image, messing up the light effect;
- updates to your plug-in, in case previous versions had known bugs.
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Old 09-08-2008, 05:24 PM
sirespen sirespen is offline
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Re: How can I avoid this?

Ok, I've found something. The problem is called banding and it apears when you misuse your image. (Probably I'm the only noob, who didn't know that )

Ciao Sebi
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Old 09-08-2008, 07:45 PM
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TommyO TommyO is offline
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Re: How can I avoid this?

Correct. Also, there are a few things you can do to avoid data loss, which results in banding or posterization:
- do most corrections to the initial image in Adobe Camera Raw first;
- stay in 16-bit mode as long as possible;
- avoid conversions between RGB and LAB;
- use adjustment layers efficiently, as well as new layers.

Again, your histogram is a good guide. Holes or spikes mean you're working inefficiently.
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Old 09-08-2008, 07:54 PM
pixelzombie pixelzombie is offline
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Re: How can I avoid this?

i've read that converting to LAB is harmless, unless you do it like 25 times..not sure of that exact number but it was in Dan Margulis book...
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Old 09-08-2008, 08:10 PM
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TommyO TommyO is offline
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Re: How can I avoid this?

The conversion to LAB from RGB, then back again is destructive due to numerical rounding. In 16-bit not as bad; 8-bit pretty bad.
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